Not a complete noob, but...

[ahedau]

I haven't been on this site in YEARS. I still see that people ask pretty lame questions rather than searching as they're supposed to. Therefore I feel free to post my interrogatory.

A friend wanted me to help him build up a 5G hatch. His ultimate goal is to AX the car. The plan was to mate a B20 bottom with the wiseco pistons I already have to an ITR head and tranny. That was the plan.

While looking for a hatch he found one already completed. It's a '95 Si. These are the mods that matter right now:

B18b1 bottom
GSR head with edelbrock adj cam gears
JR supercharger
stock header
stock Si exhaust
no Cat
GSR tranny
Hondata S300 with all the appropriate sensors working

the former owner tells me it has "after market" pistons, forged crank, ARP rod bolts, but stock rods and "aftermarket" cams. He says it's running 8 lbs of boost now but adding a CRV crank pulley would bring it up to 14 which it could handle safely.

Ok...all that to ask this. The stock exhaust has to go. I already have a 4-2-1 step header that I intended to add to a NA B20. Since this one is boosted, what's the best options for a header and what's the proper exhaust pipe size which retains as much low-end torque as the little 1800cc can put out?

I have no idea how to properly use the S300 and the Hondata site is woefully slim on any "instructions". I'd like to at least be able to see what's going on right now with the motor and make sure it's not running lean.

As always, your expert tutelage is appreciated, your flaming is not.

 

[phunky.buddha]

No idea what exhaust size you should go to or what heater to use without knowing what kind of power the engine puts out now- but I would wager a guess on a 3 inch exhaust being just fine since you have a supercharger to feed. You're probably putting down about 250whp, but that's a really wild guess based on all kinds of assumptions which are probably wrong- especially since you don't even know what's in the block.

As far as the Hondata is concerned, take it to a tuner and have them check everything out. That's about your only option at this point unless you go get a wideband sensor and your own dyno time to see how your car is configured. Hondata's site will be slim on instructions because tuning is really an art- tons of people make their livings doing it, so they're not going to give away their secrets for the world to use. Plus if it was posted up there would probably be a lot more blown engines out there blaming death on the Hondata and not bad tuning.



Good luck.

Good luck.

 

[ahedau]

Thanks. This is why I wouldn't buy someone else's project as a daily driver unless I knew them well or the build was well documented, but it wasn't my money and I wasn't consulted.

I need to call the guy that built it and get some straight answers about the internals. Supposedly it was tuned, but when and what's been done since then? Does it have "e-bay" pistons or something worth a dang? There are dozens of other questions and dozens more depending on the answers. Anyway...

I don't wanna tune it, just see what's there now to make sure it isn't going to grenade anytime soon because of detonation.

My D16Z likes 2.25" piping so I was thinking 3" would be a good guess for the s/c to breathe, but that's all it is, a guess. I'll keep looking.

 

[phunky.buddha]

You should have your buddy who bought it call the previous owner...

 

[FLounder]

i wouldnt try to go past 8 psi on the jrsc without some sort of cooling. trust me, i have experience with this. the setup you describe is probably good for about 250whp as calesta said.

you really should look into getting a 4 into 1 header with short primaries and a 2.5' collector. the old Kamikaze headers are supposedly the best for jrsc applications, but but there are other options like the RMF narrow style, and LHT makes some nice headers too.

best bet with your S300 is to find a reputable tuner that works with hondata, and have them dyno tune it. im sure the tuner will be able to give you some advice about tuning from that point on.